Spreading implements with means for varying and directing the flow of materials

ABSTRACT

A spreading implement includes at least one rotary spreading member beneath a hopper on a transportable frame with drive means connected to the rotary member. A guide is positioned adjacent the spreading member to arrest the kinetic energy imparted to material ejected and to allow the material to fall by gravity to the ground. The guide can be a screen with a configuration that varies the distance between the screen&#39;&#39;s surface and the spreading member. Thus, the distance between a segment of the screen and the spreading member can progressively decrease about the axis of rotation in the direction of rotation. The outlet in the bottom of the hopper can be positioned to feed material to the spreading member so that regulated amounts strike the screen. Such a screen can have foldable sections that are positionally adjustable to permit spreading spectrum changes. One or more spreading members with outlet regulators can be pivoted on beams relative to a frame mount so that insecticides, herbicides and the like can be directed in carefully controlled amounts along rows of trees or other crops.

United States Patent van der Lely et al.

[ 51 Aug. 8, 1972 [54] SPREADING IMPLEMENTS WITH MEANS FOR VARYING ANDDIRECTING THE FLOW OF MATERIALS [721' Inventors: Ary van der Lely, l0,Weverskade,

Maasland; Cornelis Johannes Gerar- .dus Born, 36 Esdoornlaam, Rosenburg,both of Netherlands 22 Filed: March 5, 1970 211 Appl.No.: 16,732

[30] Foreign Application Priority Data Voich et al. ..239/666 PrimaryExaminer-M. Henson Wood, Jr. Assistant ExaminerJohn J. LoveAttorney-Mason, Mason & Albright [57] ABSTRACT A spreading implementincludes at least one rotary spreading member beneath a hopper on atransportable frame with drive means connected to the rotary member. Aguide is positioned adjacent the spreading member to arrest the kineticenergy imparted to material ejected and to allow the material to fall bygravity to the ground. The guide can be a screen with a configurationthat varies the distance between the screens surface and the spreadingmember. Thus, the distance between a segment of the screen and thespreading member can progressively decrease about the axis of rotationin the direction-of rotation. The outlet in the bottom of the hopper canbe positioned to feed material to the spreading member so that regulatedamounts strike the screen. Such a screen can have foldable sections thatare positionally adjustable to permit spreading spectrum changes. One ormore a spreading members with outlet regulators can be pivoted on beamsrelative to a frame mount so that insecticides, herbicides and the likecan be directed in carefully controlled amounts along rows of trees orother crops.

36 Claims, 8 Drawing Figures rmminws' 1912 3.682.395

SHEEI 1 UF 4 iM d IINVENTORS PATENTEDMI lm 3.682.395

SHEET k [If 4 SPREADING IMPLEMENTS WITH MEANS FOR VARYING AND DIRECTIN GTHE FLOW OF MATERIALS An object of the invention is the provision of animplement of the kind specified above which is capable of distributingsmall quantities per unit area of materials, such as herbicides, simplyand effectively around trees, shrubs and the like standing in rows.

According to one aspect of the invention, there is provided a spreadingimplement of the kind set forth, wherein the implement includes means toremove kinetic energy from material ejected by the spreading memberduring the use of the implement, said means being located at a shortdistance from the spreading member which is such that, after beingsubject to the action of said means, gravity is substantially the onlyforce acting upon the material.

For a better understanding of the invention, and to 'show how the samemay be carried into effect,

reference will now be made, by way of example, to the accompanyingdrawings, in which:

FIG. 1 is a plan view illustrating the operation of a 3 dual spreadingimplement in accordance with the invention, the implement beingconnected to the threepoint lifting device or hitch of a tractor,

FIG. 2 is a plan view, to an enlarged scale, showing further details ofone of the two implements illustrated in FIG. 1,

FIG. 3 is a section, to an enlarged scale, taken on the line III-III ofFIG. 1,

FIG. 4 is a diagram illustrating a distribution spectrum of theimplement,

FIG. 5 corresponds to FIG. 2 but shows the implement provided with analternative part,

FIG. 6 is a diagram illustrating the distribution spectrum which isobtained when the implement is provided with the alternative partillustrated in FIG. 5,

FIG. 7 again generally corresponds to FIG. 2 but shows a furtheralternative part, and

FIG. 8 once again corresponds to FIG. 2 but shows a still furtheralternative part.

Referring to FIG. 1 of the drawings, the spreading or distributingimplement which is illustrated in that Figure is a dual implementintended principally for distributing powdered and granular materials,such as herbicides, between trees, shrubs and other plants that stand inrows in orchards, fields and the like. An operating tractor 2 has athree-point lifting device or hitch l and two oppositely directed framebeams 3 and 4 are tumably about a central substantially vertical pivot 5carried by a supporting structure 6' that is mounted on the three-pointlifting device 1 in a generally conventional manner. The two frame beams-3 and 4 are of tubular construction and the ends 7 and 8 thereof thatare remote from the central pivot 5 respectively carry the two spreadingportions 9 and 10 of the dual implement. The ends 7 and 8 of the beams 3and 4 are of solid formation and square cross-section (see FIG. 3) andeach of the two spreading portions9 and 10 is connected thereto bysupporting arms 1 1 and substantially vertical retaining pins or thelike 12.

The spreading portions 9 and 10 have corresponding driving mechanisms 13and 14 respectively with the aid of each of which mechanisms centralsubstantially vertical driving shafts 15 of the two portions 9 and 10can be rotated. A double pulley 17 (FIG. 1) is rotatable about asubstantially vertical axis coincident with that of the central pivot 5and is driven from the power take-off shaft of the tractor 2 with theaid of a simple mechanism which is not illustrated in the drawings. V-belts, ropes or the like 18 and 19 pass around the two pulleys 17 andare directed laterally in relatively opposite directions towards theends 7 and 8 of the two beams3and4. AscanbeseeninFIGS. 2and3ofthedrawings in respect of the driving mechanism 14, the V-belt, rope or thelike 19 passes around one pulley of a double pulley 54 from the otherpulley of which a V- belt, rope or the like 53 transmits the drive tothe corresponding shaft 15 by way of a pulley 52 that is secured to thelowermost end of that shaft. The driving mechanism 13 is symmetricallysimilar except that the V-belt, rope or the like which corresponds tothe belt or rope 53 is crossed (see FIG. 1) to ensure that the twoshafts 15 rotate in opposite directions.

The supporting structure 6 includes a large control disc 20.that issubstantially horizontally disposed and that has a curved edge whosecenter of curvature is coincident with the axis of the central pivot 5.A number of holes 21 are formed through the disc 20 around the curvededge and those parts of the two arms 3 and 4 which are tumable aroundthe pivot 5 over the edge region of the disc 20 carry blocks 22 and 23respectively through which substantially vertical holes 24 are formed.The arms 3 and 4 can be turned around the central pivot 5 until theholes 24 come into register with chosen ones of the holes 21. Verticallocking pins 25 can then be entered through the aligned holes to retainthe arms 3 and 4 in the chosen angular settings around the pivot 5. Theworking width of the dual implement can thus be varied. A maximumworking width in which the two spreading portions 9 and 10 are at amaximum distance apart from one another is obtained by entering thelocking pins 25 through the holes 24 and those holes 21 in the disc 20which are furthest remote from one another. The maximum working widthwhich has just been mentioned is advantageously about 6 meters. The dualimplement can be placed in a position suitable for the non-operativetransport thereof in which its width is reducedto a minimum. Thisposition is reached by turning the two frame beams 3 and 4 towards oneanother about the central pivot 5 until the holes 24 are in registerwith the two holes 21 that are located closest to the opposite sides ofa central substantially vertical plane of symmetry 16 of the implementthat extends parallel to the intended direction of operative travel 58(FIG. 1) thereof. Simple and safe transport of the implement is thuspossible. I-Ielical tension springs 26 extend between the frame beams 3and 4 and parts of the supporting structure 6 and the blocks 22 and 23may, if desired, be omitted so that the springs 26 hold the beams 3 and4 against stops while allowing said beams to yield rearwardly about thecentral pivot 5 upon meeting immovable obstacles. To this end, thesprings 26 are provided with known mechanisms (not shown) to enable themto be stretched as required. Either by using the blocks 22 and 23 or byusing the springs 26 in combination with stops, the working width of thedual implement can readily be adjusted to match the different spacingsbetween rows 27 and 28 of trees, shrubs and the like.

The two spreading portions 9 and 10 are symmetrically identical apartfrom the previously mentioned dispositions of the belts, ropes or thelike 53 of the two driving mechanisms 13 and 14. The spreading portion10 which is shown in greater detail in FIGS. 2 and 3 of 5 the drawingshas a container in the form of a hopper 29 of inverted frusto-conicalconfiguration. A rotary spreading member 34 is disposed beneath thebottom of the hopper 29 and takes the form of a square disc providedwith four curved spreading blades 35 on its upper surface, the radiallyoutermost ends of the blades 35 being located at the four corners of thesquare disc. The center of the spreading member 34 is, of course,secured to the driving shaft above the pulley 52, said shaft beingrotatably journalled in a substantially vertical bearing (not visible inthe drawings) carried by the bottom 30 of the hopper 29. Beneath thehopper bottom 30, upper and lower discs 31 and 32 are turnable relativeto one another about the shaft 15 and are also turnable, in common,about that shaft. Means is provided for securing the discs 31 and 32 inchosen angular settings about the shaft 15 and a control arm 43 thatprojects forwardly is provided for varying the angular setting as may berequired. The bottom 30 of the hopper 29 has a semi-circular outlet port32A and the two underlying discs 31 and 32 are provided with outletopenings 33 that are of substantially rectangular configuration in thisparticular embodiment. The relative angular settings of the two discs 31and 32 determine the degree of overlap, or otherwise, of the openings 33and thus the effective size of the port through which material from thehopper 29 can reach the spreading member 34. The angular setting of thiseffective opening around the shaft 15 is the principal factor indetermining the direction in which the spreading member 34 ejects thematerial from the spreading portion 10. Each opening 33 preferably hasan area which is not greater than 5 square centimeters and each openingpreferably has a maximum radial width of not more than 1 centimeter.

A strip-like fastening bracket 50 is secured to the inclined wall of thehopper 29 at the front thereof relative to the direction 58. A support51 is bolted to the bracket 50 and the previously mentioned control arm43 is turnable about a pivot bolt mounted at the free end of the support51. The upper ends of the supporting arms 11 by which the hopper 29 isfastened to the frame beam 4 are also bolted to the bracket 50 below thesupport 51. The previously mentioned double pulley 54 of the drivingmechanism 14 is rotatably mounted at the leading downwardly bent-overend of a rod 55 whose main horizontal limb is of square crosssection.The horizontal limb of the rod 55 is carried at the leading end of asupport 56 which projects forwardly and downwardly from the bracket 50to which latter it is bolted by the same bolts as are used in respect ofthe supporting arms 1 l. The arrangement is, in fact, such that avertical set bolt having a lock nut provided at the leading end of thesupport 56 can be employed to retain the rod 55 in a chosen setting ofextension beyond the support 56 in the direction 58. The V-belt,-rope orthe like 53 can thus be tensioned as required.

The uppermost edge of the hopper 29 has a guide screen 36 connected toit. A rail-like bracket 37 has its opposite ends secured'to theuppermost edge of the hopper 29 by short strips 38 while anapproximately central region thereof is connected to the uppermost edgeby a longer strip 39. The uppermost edge of the substantially verticallydisposed guide screen 36 is itself secured to the bracket 37 by smallbolts or rivets 41. The guide screen 36 is preferably formed wholly orpartly from a material that is capable of absorbing a large proportionof the kinetic energy of any moving article which strikes it. Materialssuch as, for example, foam rubber, polyurethane foam or some otherfoamed synthetic plastics material has been found to be suitable. Aswill be evident from FIG. 2 of the drawings, the bracket 37, andtherefore the guide screen 36, is not symmetrical with respect to theopposite sides of a substantially vertical plane 57 containing the axisof rotation of the shaft 15 and extending parallel to the direction 58.That portion of the screen 36 which is to the right-hand side of theplane 57 with respect to the direction 58 is cylindrically curved insuch a way that the center of curvature is substantially coincident withthe longitudinal axis of the shaft 15, said portion subtending an angle59 of about 120 at said shaft. The portion of the guide screen 36 whichis located at the left-hand side of the plane 57 with respect to thedirection 58 is irregularly curved but nevertheless subtends an angle 60at the axis of the shaft 15 which also has a magnitude of about 120.FIG. 2 of the drawings shows, in plan, a line 61 extending radially fromthe shaft 15 through that end of the bracket 37 which is to theleft-hand side of the plane 57 with respect to the direction 58. It willbe noted that the line 61 intersects, in plan view, the outlet openings33. That point on the bracket 37 and guide screen 36 which, in the planview of FIG. 2, is furthest from the shaft 15 is denoted by thereference 62 and it will be noted that the angle 63 which is enclosedbetween the radial line 61 and a radial line 64 (extending from theshaft 15 through the point 62) has a magnitude of about The point 62 islocated at a perpendicular distance from the shaft 15 which ispreferably not less than about twice the perpendicular distance betweenthat shaft and the radially outermost end of any one of the spreadingblades 35. Conversely, it is preferred that the first of the twodistances just mentioned should not exceed four times the second ofthose distances. The distance preferably has a value of between 20 and50 centimeters and, in the particular embodiment, which is beingdescribed, the point 62 is spaced along the line 64 from the shaft 15 bya distance which is about 2 56 times the perpendicular distance betweenthe shaft 15 and the radially outermost end of one of the spreadingblades 35. The point 62 is located on that side of the plane 61 towhich, in the plan view of FIG. 2, the disc of the spreading member 34is turning by intersecting the vertical plane 61. It will be noted that,while the irregularly curved portion of the guide screen 36 associatedwith the point 62 is located to the left-hand side of the plane 57 (withrespect to the direction 58) in the case of the spreading portion 10(FIG. 2), the corresponding irregularly curved portion of the screen 36and bracket 37 is located to the right-hand side of a correspondingplane in the case of the spreading portion 9 (FIG. 1).

As can be seen in FIG. 3 of the drawings, the lowermost edge of theguide screen 36 is secured to a bracket 40 that is somewhat similar tothe bracket 37, further small bolts or rivets 41 being employed to thisend. However, it is preferred that the bracket 40 should be heavy inweight so that the flexible screen 36 will hang more or less verticallyin a taut condition during operation of the implement. It is alsopreferred that a compression spring or coil spring 42 (FIG. 3) shouldextend between the two brackets 37 and 40 to tend to maintain driven torotate the spreading member 34 of the spreading portion 10in thedirection D (FIGS. 1 and 2) and the spreading member 34 of the spreadingportion 9 in an opposite direction (see FIG. 1). The outlet openings 33are adjusted relative to each other and in common relative to the outletport 32A so that the desired quantity of material per unit time flowsfrom each hopper 29 to each spreading member 34. The shapes anddimensions of the outlet ports and openings are such that the implementis capable of distributing quantities of herbicides and like materialsof about 80 kilograms per hectare (71.25 pounds per acre). The sizes ofthe effective outlet ports through the hopper bottoms 30 will, ofcourse, be adjusted to suit the speed of travel of the implement.

The rapid rotation of each spreading member disc 34 causes the powderedor granular material which falls thereon to be spread centrifugally bythe blades 35 in a direction such that almost all of that materialstrikes the screens 36. The kinetic energy of the material is ab sorbedby the screens 36 and its velocity in a horizontal direction relative tothe screens is thus reduced substantially to zero. Gravity remains asthe only strong force tending to move the material and the material thusdrops downwardly along the screens 36. In order to ensure that all, or avery large proportion, of the material strikes the screens 36 and isguided downwardly thereby as required, each screen 36 has a largevertical extent 65 (FIG. 3) downwardly from the uppermost edge of thecorresponding hopper 29, part of each screen 36 extending below thecorresponding spreading member 34 throughout a vertical distance 68.Although it is preferred to employ the heavy lower brackets 40 to ensurethat the screens 36 remain more or less vertically disposed, it is notabsolutely essential to employ these brackets when the screens 36 aremade from, or include, materials which are of sufficient rigidity inthemselves.

It will be appreciated that the guide screens 36 are detachable from thespreading portions 9 and 10 but,

when they are employed, a distribution spectrum for the spread materialsimilar to that shown in FIG. 4is produced, the material being spreadthroughout a' the shaft 15 also effects the magnitude of the width 67.

The spreading implement which is illustrated in the drawings by way ofexample is arranged for distributing herbicides and like materials inthe form of small granules, crystals and other similar particles. Thescreens 36 are disposed to suit the spreading of such materials and theaforementioned vertical distance 68 is approximately half the verticaldistance 69 between the spreading member 34 and the ground surface. Theimplement is particularly suitable for spreading herbicides,insecticides and other pesticides in granular, powdered, crystalline orother particulate forms since such materials generally need to bedistributed very uniformly at small weights per unit area such as aboutkilograms per hectare (71.25 pounds per acre). With such rates ,ofdistribution, only about 3 or 4 average grains of the material shouldfall upon each square centimeter of ground. The screens 36 are effectivein producing uniform distributions of this order and, when arranged asshown in FIGS. 1 to 3 of the drawings, keep the material strictly withinthe sharply defined width 67 indicated in FIG. 4.

The screens 36 should be moved in position in dependence upon theangular setting of the outlet openings 33 around the shafts 15 and theirdistances from the planes 57. If alteration of the position of the discs31 and 32 about the axes of the shafts 15 is found to be necessary, thenit is most desirable that the screens 36 should also be moved aroundthose axes. The angular displacement of the screens 36 should besubstantially equal to the common displacement of the discs 31 and 32.The shapes and positions of the screens 36 are such that the herbicideor other material strikes them along lines of impact making angles of orsubstantially 90, with tangents to their surfaces at the actual pointsof impact. When the spreading portion 10 is arranged as shown in FIGS.1, 2 and 3 of the drawings, the material ejected by the spreading member34 strikes the screen 36 throughout an area subtending an angle of about65 at the axis of the corresponding shaft 15. As can be seen in FIG. 2of the drawings, a part of this area subtending an angle of about 15 atthe shaft 15 is located to the right-hand side of the plane 57 withrespect to the direction 58 whereas a part thereof subtending about 50at the shaft 15 is located on the opposite side of said plane. Theposition of the area subtending the angle 100, its size, the speed ofrotation of the spreading member 34 and the angular setting of theoutlet openings 33 about the shaft 15 are all interdependent. Thedesired distribution spectrum is obtained by arranging each screen 36 ata short distance from the corresponding spreading member 34 and it willbe noted that the outermost point 62 of the screen 36 of the spreadingportion 10 is located on the radial line 64 and that the aforementionedangle 100 is enclosed between said line 64 and a further radial line101. With respect to the intended direction of rotation D of thespreading member 34, the point 62 is in line with the leading boundary64 of the angle 100 and the radial distance of the screen .36 andbracket 37 from the shaft 15 progressively decreases towards theboundary line 101 of the angle 100 as a blade 35 passes through theangle 100 in the direction D. The perpendicular distance between thescreen 36 and the shaft 15 is at about its minimum the plan view of FIG.2) by the radial line 101 disre garding the two ends of the screen atwhich the bracket 37 is fixed to the strips 38. Provided that at leastthe concave surface of each screen 36 against-which the material strikesis formed from an energy-absorbent composition, there will be verylittle, if any, tendency for the impacting material to bouncesubstantially horizontally away from the screens. The material thusdrops more or less vertically downwards after impact so that the screens36 themselves sharply define the distribution area. To this end, it isdesirable, although not absolutely essential, that the impacttrajectories of the particles of material should be as nearlyperpendicular as possible to tangents to the surface of the screens 36at the individual points of impact. It is noted once again that theoperation of the spreading portion 9 is substantially symmetricallyidentical to that of the spreading portion 10 shown in detail in FIGS. 2and 3 of the drawings. It is also noted that, while it is convenient andeconomic to form a spreading implement in accordance with the inventionas a dualimplement in the manner illustrated in FIG. 1 of the drawings,this is by no means essential and it is within the scope of the invention to provide a single implement that projects only to the left, oronly to the right, of the plane 16 shown in FIG. 1.

FIG. 5 of the drawings substantially corresponds to FIG. 2 butillustrates the provision of a guide screen 70 that is of a differentconstruction to the previously described guide screen 36. Parts that aresimilar, or identical, to parts that have already been described areindicated in FIG. 5 (and in FIGS. 7 and 8) of the drawings by the samereference numerals as are employed for those parts in FIGS. 1 to 3 ofthe drawings. It will be noted that the outlet openings 33 are shown inFIG. 5 of the drawings occupying the same positions as illustrated inFIG. 2. That part of the guide screen 70 which is located to the rightof the plane 57 with respect to the direction 58 has substantially thesame shape and disposition as the corresponding part of the guide screen36 of the spreading portion 10 in the embodiment of FIGS. 1 to 3.However, that part of the guide screen 70 which is located to the leftof the plane 57 with respect to the direction 58 is much smaller thanthe corresponding part of the guide screen 36 and subtends an angle 71of only about 40 magnitude at the axis of the shaft 15. Nevertheless,the part of the screen 70 which subtends the angle 71 has the same shapeand disposition as the corresponding region of the screen 36. With thediscs 31 and 32 adjusted to position the outlet openings 33 asillustrated in FIG. 5, material is spread from the member 34 by theblades 35 substantially only throughout a sector bounded, in plan view,at one end by a radial line 72 and at the opposite end by the previouslymentioned radial line 101. The screen 70 registers with only part ofthis sector so that material leaving the spreading member 34 through anangular sector around the axis of the shaft that is bounded by the line72 and by a line passing through the free outermost end of the screen 70does not strike that screen at all and is therefore not prevented frommoving further outwards away from the spreading member 34.

When materials such as herbicides in the form of small granules,crystals or other particles are to be spread by the implement, the guidescreen 70 provides a distribution spectrum similar to that showndiagrammatically in FIG. 6. The herbicide, insecticide or otherpesticide is substantially evenly distributed throughout a width 73measured in a substantially horizontal direction perpendicular to thedirection 58 whereas the weight of material which reaches the ground perunit area progressively decreases over a width 74 extending outwardlyaway from the plane 57. The distribution spectrum shown in FIG. 6 isvery effective for treating rows of trees, shrubs or the like withherbicides, insecticides and the like and, in FIG. 6 of the drawings,the position of the row is diagrammatically illustrated by the brokenvertical line 75. If an implement similar to the single implement ofFIG. 5 passes the row indicated by the line 75 at the opposite sidethereof to the first pass and in an opposite direction to the direction58, then a second symmetrical distribution spectrum shown in FIG. 6 inbroken lines is obtained. By operating in this way, an overalldistribution width 76 is obtained that extends equal distances to theopposite sides of the row indicated by the line 75. The amount ofherbicide or the like which is spread per unit area of ground issubstantially uniform throughout the distribution width 76 except for aslight reduction immediately around the trees or shrubs affording therow indicated by the line 75.

FIG. 7 shows a further alternative construction in which the guidescreen 36 of FIG. 2 is replaced by a guide screen that is generallyindicated by the reference 80. The guide screen 80 has the same shape asthe guide screen 36 and comprises a portion 81 subtending an angle 82 atthe axis of the shaft 15 which is equal to the angle subtended by theguide screen 70 of FIG. 5. However, the guide screen 80 has a secondportion 83 which can either occupy a position in which it subtends anangle 84 at the axis of the shaft 15 or a folded-back position (asillustrated) in which it is disposed behind the portion 81 when viewedfrom the shaft 15. Buttons or other known releasable fastenings 85 areemployed to maintain the portion 83 in the ineffective folded-backposition shown in FIG. 7 of the drawings and at least one of saidbuttons or the like 85 may be employed to connect the free end of theportion 83 to the short strip 38 at the upper right of FIG. 7 of thedrawings when said portion 83 occupies its operative position. It willbe realized from the preceding description that, when the portion 83 ofthe guide screen 80 occupies its operative position, a distributionspectrum similar to that shown in FIG. 4 of the drawings will beobtained whereas, when it occupies its inoperative position, asillustrated in FIG. 7, a distribution spectrum similar to that describedwith reference to FIG. 6 of the drawings will be obtained.

FIG. 8 of the drawings shows a still further alternative construction inwhich a guide screen is provided having a substantially fixed portion 91that corresponds to the portion 81 described with reference to FIG. 7.In this case, the bracket 37 is replaced by a bracket having a fixedportion 94 and a pivotable portion 93, the latter portion 93 beingtumable relative to the fixed portion about a substantially verticalpivot 95. The pivotable portion 93 of the bracket carries a movableportion 92 of the guide screen 90. The pivot defines an axis whichextends substantially parallel to the more or less vertical axis of theshaft 15. The fixed portion 94 of the bracket and the fixed portion 91of the guide screen 90 which it carries subtend an angle 82 (FIG. 7) atthe axis of the shaft 15 and the pivotable portion 93 of said bracketsubtends, together with the movable portion 92 of said screen, an angle84 (FIG. 7) at the axis of the shaft 15 when turned about the pivot 95from the illustrated inoperative position into an operative position. Ascan be seen in FIG. 8 of the drawings, a retaining rod 96 has itsdownwardly bent-over end entered through a hole in the pivotable portion93 of the bracket to retain the movable portion 92 of the guide screenin the illustrated inoperative position in which it is behind the fixedportion 91 of the guide screen when viewed from the shaft 15. Thebent-over end of the rod 96 is entered through a hole in the fixedportion 94 of thebracket when the movable portion 92 of the guide screen90 occupies its operative position. The end 97 of the pivotable portion93 of the bracket that is remote from the pivot 95 carries a simpleclamp 98 to enable it to be releasably secured to the uppermost edge ofthe hopper 29 when a distribution spectrum similar to that illustratedin FIG. 4 is desired for the material spread by the implement. When themovable portion 92 is folded back as shown in FIG. 8 of the drawings, adistribution spectrum similar to that illustrated .in FIG. 6 is obtainedbecause the angle 71 (FIG. is some 10 to smaller in magnitude than theangle enclosed between the line 64 (FIG. 2) and the plane 57 or line101. This allows some of the ejected material to pass by the guidescreen without hindrance.

Although all of the spreading members 34 that have been described rotatein the anticlockwise direction D as seen in plan view, it will beself-evident that an opposite direction of rotation could be employed inwhich case guide screens should be used that are symmetrically oppositein construction with respect to the plane 57. An example of this can, ofcourse, be seen in the case of the dual implement of FIG. 1 where theguide screen 36 and rail-like bracket 37 associated with the spreadingportion 9 are symmetrical to those associated with the spreading portion10.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent. of the United States is:

l. A spreading implement comprising a transportable frame, with a hopperand a rotary spreader being supported on said frame, said hopper havingoutlet means adjacent the bottom thereof and said spreader beingpositioned below said outlet means, a guide screen having concavesurfaces being located adjacent said spreader generally to the rearthereof to arrest the movements of ejected material, said screen beingpartly positioned in the spreading spectrum defined by material normallyejected by said spreader with the distance between said concave surfacesand the axis of rotation of said spreader being varied, whereby saiddistance decreases in the direction of rotation of said spreader whenthe same is viewed in top plan.

2. An implement as claimed in claim 1, wherein at least part of thespreading spectrum of said spreader is surrounded by said guide screenand the latter is comprised of a shock-absorbent material.

3. An implement as claimed in claim in claim 2, wherein said material isa synthetic plastics foam.

4. An implement as claimed in claim 1, wherein the maximum distancebetween said guide screen and the axis of rotation of said spreader isnot greater than three times the minimum distance between said screenand said axis.

5. An implement as claimed in claim I, wherein the maximum distancebetween said guide screen and the axis of rotation of the spreader isnot greater than 150 centimeters.

6. An implement as claimed in claim 1, wherein the concave surfaces ofthe guide screen occupies a substantially fixed angular setting aroundthe axis of rotation of said spreader and said surfaces are positionedin only that spectrum around said axis into which material is normallyejected by said spreader during operation.

7. An implement as claimed in claim 6, wherein a portion of said guidescreen is located a distance from the axis of rotation of said spreaderand said distance decreases along its length at a point approximatelyhalfway around the axis of rotation from a line extending forwardly fromthat axis in the normal direction of travel.

8. An implement as claimed in claim 1, wherein a radial line extendingfrom the axis of rotation of said spreader through the center of anopening of said outlet means is inclined at an angle of about to afurther radial line passing through that end of said guide screen whichis foremost with respect to the direction of rotation of said spreader.

9. An implement as claimed in claim 1, wherein a radial line extendingfrom the axis of rotation of said spreader through the center of anopening of said'outlet means is inclined at an angle of about 70 to afurther radial line passing through that point of said guide screenwhich is at the greatest distance from the axis of rotation of saidspreader.

10. An implement as claimed in claim 9, wherein said point on the guidescreen is located at a distance from the axis of rotation of saidspreader that is not less than twice and not more than four times theeffective radius of the spreader.

11. An implement as claimed in claim 10, wherein said distance is about2 /2 times the effective radius of said spreader.

12. An implement as claimed in claim 1, wherein said spreader includes adisc on a substantially vertical shaft and that portion of said guidescreen, which is located nearest to the axis of rotation of saidspreader, is spaced from that axis by a distance less than twice theeffective radius of said disc.

13. An implement as claimed in claim 1, wherein a portion of said guidescreen is located a distance from the axis of rotation of said spreaderwhich distance decreases along its length and subtends an angle ofapproximately 70 at said axis of rotation, said guide screen alsoincluding a further portion with a concave surface curved so that itscenter of curvature is substantially coincident with said axis ofrotation.

14. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being supported on said frame, said hopperhaving outlet means adjacent the bottom thereof and said outlet meansbeing positioned in a predetermined place relative to the axis ofrotation of the spreader in such a way that during operation of thedevice the material is spread out over only an angular sector, saidspreader being positioned below said outlet means, a guide screen havingconcave surfaces being supported on said implement and located adjacentsaid spreader generally to the rear thereof relative to the direction oftravel, said screen extending over said angular sector to arrest themovements of ejected material, the distance between said concavesurfaces and the axis of rotation of said spreader being varied, wherebythe maximum distance of said concave surfaces to the axis of rotation ofthe spreader is not greater than two and a half times the distancebetween the outer circumference of the spreader and its axis ofrotation.

15. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being mounted on said frame, said spreaderbeing located below said hopper and adjustable outlet means in saidhopper for metering material to said spreader, said outlet means beingadjustably positioned relative to the axis of rotation of the spreaderwhereby, during operation, material is spread out to be concentratedover a selected angular sector, guide means supported on a bracketconnected to said frame, to present concave surfaces that surround atleast a portion of said rotary spreader, said guide means comprising ascreen extending over at least part of the selected angular sector toarrest the movement of controlled amounts of material ejected by saidspreader, thereby allowing the material to fall by gravity to the groundin a predetermined spectrum and concentration, a first portion-of saidguide screen being detachable from said bracket and securing meansassociated with said bracket to retain said first portion at a secondposition in back of a second portion of said guide screen.

16. An implement as claimed in claim 15, wherein said outlet meanscomprises an outlet port in the bottom of said hopper and control discs,each with outlet openings that can be placed in register with said port,said discs being located between said hopper and said spreader.

17. An implement as claimed in claim 15, wherein said second portion isconnectable to said bracket by a readily detachable fastening member onsaid bracket.

18. An implement as claimed in claim 15, wherein said first portion ofthe guide screen is pivotally connected to said second portion which isfixed to said bracket.

.19. An implement as claimed in claim 18, wherein said first portion istumable relative to said second portion about a pivot whose axis extendssubstantially parallel to the axis of rotation of said spreader.

20. An implement as claimed in claim 15, wherein said first portion isconnected to said second portion at a point which is at a maximumdistance from the axis of rotation of said spreader, said guide screenbeing positioned whereby the distance between said axis and the screenprogressively decreases in both directions when seen in top plan view.

21. An implement as claimed in claim 15, wherein the first portion ofsaid guide screen has one of its ends located adjacent to, a radial linewhich, in plan view, passes through the axis of rotation of saidspreader and through said outlet means.

22. An implement as claimed in claim 15, wherein said guide screen has alength of not more than 2 meters.

23. An implement as claimed in claim 15, wherein ter.

24. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being mounted on said frame, said spreaderbeing located below said hopper and adjustable outlet means in saidhopper for metering material to said spreader, said outlet means beingadjustably positioned relative to the axis of rotation of the spreaderwhereby, during operation, material is spread out to be concentratedover a selected angular sector, guide means supported on said implementto present concave surfaces that surround at least a portion of saidrotary spreader, said guide means extending over at least part of theselected angular sector to arrest the movement of controlled amounts ofmaterial ejected by said spreader, thereby allowing the material to fallby gravity to the ground in a predetermined spectrum and concentration,said guide means comprising a guide screen, the area of which isadjustable to present more or less concave surfaces adjacent saidspreader.

25. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being mounted on said frame, said spreaderbeing located below said hopper and adjustable outlet means in saidhopper for metering material to said spreader, said outlet means beingadjustably positioned relative to the axis of rotation of the spreaderwhereby, during operation, material is spread out to be concentratedover a selected angular sector, guide means supported on said implementto present concave surfaces that surround at least a portion of saidrotary spreader, said guide means extending over the selected angularsector to arrest the movement of controlled amounts of material ejectedby said spreader, thereby allowing the material to fall by gravity tothe ground in a predetermined spectrum and concentration, the distancebetween said concave surfaces and the axis of rotation of said spreaderbeing varied, said guide means comprising a screen positioned tosurround a portion of said spreader whereby the trajectory of particlesof ejected material interceptedby said screen are at angles of 45relative to tangents to said screen at the points of impact.

26. An implement as claimed in claim 25, wherein said glide screensubtends a maximum angle of about 240 at the axis of rotation of saidspreader and one end of said guide screen is located adjacent a radialline extending from said axis through the center of said outlet port.

27. .An implement as claimed in claim 25, wherein the lowermost edge ofsaid guide screen is located at a distance above ground level which isnot more than half the distance of said spreader above the ground.

28. An implement as claimed in claim 25, wherein, not le$ than abouthalf the height of said guide screen is located above said spreader.

29. An implement as claimed in claim 28, wherein said guide screen isfastened to said implement adjacent the upper rim of said hopper and thelatter is located directly over and above said spreader.

30. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being mounted on said frame, said spreaderbeing located below said hopper and outlet means with at least oneoutlet opening being provided in the lower end of the hopper formetering material from said hopper to said spreader, said outlet meansbeing positioned in a predetermined place relative to the axis ofrotation of through said outlet opening being inclined at an angle ofabout 70 to a further radial line passing through that point of saidguide means which is at the greatest distance from the axis of rotationof said spreader.

31. A spreading implement comprising a transportable frame, with ahopper and a rotary spreader being mounted on said frame, said spreaderbeing located below said hopper and outlet means with at least oneoutlet opening being provided in the lower end of the hopper formetering material to said spreader, during operation of the device saidoutlet means being positioned in a predetermined place relative to theaxis of rotation of the spreader whereby material ejected from saidspreader is spread out over only an angular sector, guide meanssupported on said implement to present concave surfaces that surround atleast a portion of said rotary spreader, said guide means extending atleast substantially over the selected angular sector to arrest themovement of ejected material, the distance between said concave surfacesand the axis of rotation of said spreader being varied, that area ofsaid surface on said guide means which is most distal from the axis ofrotation of said spreader being angularly spaced from a radial lineextending from the axis of rotation of said spreader through said outletopening, at least part of said concave surfaces extending around thespreader from said most distal area of the guide means in the directionof rotation of said spreading member, whereby the distance between atleast a portion of said part of the concave surfaces and said axis ofrotation decreases as seen in the direction of rotation of saidspreader.

32. An implement as claimed in claim 24, wherein said guide screen issupported on bracket means attached to said frame and an upper bracketof said bracket means effects a connection between said screen and saidhopper.

33. An implement as claimed in claim 32, wherein said upper bracket isconnected to said hopper at three substantially equally spaced-apartpoints.

34. An implement as claimed in claim 32, wherein a lower bracket of saidbracket means is spaced from the ground by a distance of not more thanabout 10 centimeters.

35. An implement as claimed in claim 34, wherein at least one stiffeningelement extends between said upper and lower brackets to increase therigidity of said screen.

36. An implement as claimed in claim 35, wherein said stiffening elementis resilient to permit upward and lateral deflections of said lowerbracket relative to said upper bracket.

1. A spreading implement comprising a transportable frame, with a hopperand a rotary spreader being supported on said frame, said hopper havingoutlet meaNs adjacent the bottom thereof and said spreader beingpositioned below said outlet means, a guide screen having concavesurfaces being located adjacent said spreader generally to the rearthereof to arrest the movements of ejected material, said screen beingpartly positioned in the spreading spectrum defined by material normallyejected by said spreader with the distance between said concave surfacesand the axis of rotation of said spreader being varied, whereby saiddistance decreases in the direction of rotation of said spreader whenthe same is viewed in top plan.
 2. An implement as claimed in claim 1,wherein at least part of the spreading spectrum of said spreader issurrounded by said guide screen and the latter is comprised of ashock-absorbent material.
 3. An implement as claimed in claim in claim2, wherein said material is a synthetic plastics foam.
 4. An implementas claimed in claim 1, wherein the maximum distance between said guidescreen and the axis of rotation of said spreader is not greater thanthree times the minimum distance between said screen and said axis. 5.An implement as claimed in claim 1, wherein the maximum distance betweensaid guide screen and the axis of rotation of the spreader is notgreater than 150 centimeters.
 6. An implement as claimed in claim 1,wherein the concave surfaces of the guide screen occupies asubstantially fixed angular setting around the axis of rotation of saidspreader and said surfaces are positioned in only that spectrum aroundsaid axis into which material is normally ejected by said spreaderduring operation.
 7. An implement as claimed in claim 6, wherein aportion of said guide screen is located a distance from the axis ofrotation of said spreader and said distance decreases along its lengthat a point approximately half-way around the axis of rotation from aline extending forwardly from that axis in the normal direction oftravel.
 8. An implement as claimed in claim 1, wherein a radial lineextending from the axis of rotation of said spreader through the centerof an opening of said outlet means is inclined at an angle of about 70*to a further radial line passing through that end of said guide screenwhich is foremost with respect to the direction of rotation of saidspreader.
 9. An implement as claimed in claim 1, wherein a radial lineextending from the axis of rotation of said spreader through the centerof an opening of said outlet means is inclined at an angle of about 70*to a further radial line passing through that point of said guide screenwhich is at the greatest distance from the axis of rotation of saidspreader.
 10. An implement as claimed in claim 9, wherein said point onthe guide screen is located at a distance from the axis of rotation ofsaid spreader that is not less than twice and not more than four timesthe effective radius of the spreader.
 11. An implement as claimed inclaim 10, wherein said distance is about 2 1/2 times the effectiveradius of said spreader.
 12. An implement as claimed in claim 1, whereinsaid spreader includes a disc on a substantially vertical shaft and thatportion of said guide screen, which is located nearest to the axis ofrotation of said spreader, is spaced from that axis by a distance lessthan twice the effective radius of said disc.
 13. An implement asclaimed in claim 1, wherein a portion of said guide screen is located adistance from the axis of rotation of said spreader which distancedecreases along its length and subtends an angle of approximately 70* atsaid axis of rotation, said guide screen also including a furtherportion with a concave surface curved so that its center of curvature issubstantially coincident with said axis of rotation.
 14. A spreadingimplement comprising a transportable frame, with a hopper and a rotaryspreader being supported on said frame, said hopper having outlet meansadjacent the bottom thereof and said outlet means being positioned in apredetermined place relative to the axis of rotation of the spreader insuch a way that during operation of the device the material is spreadout over only an angular sector, said spreader being positioned belowsaid outlet means, a guide screen having concave surfaces beingsupported on said implement and located adjacent said spreader generallyto the rear thereof relative to the direction of travel, said screenextending over said angular sector to arrest the movements of ejectedmaterial, the distance between said concave surfaces and the axis ofrotation of said spreader being varied, whereby the maximum distance ofsaid concave surfaces to the axis of rotation of the spreader is notgreater than two and a half times the distance between the outercircumference of the spreader and its axis of rotation.
 15. A spreadingimplement comprising a transportable frame, with a hopper and a rotaryspreader being mounted on said frame, said spreader being located belowsaid hopper and adjustable outlet means in said hopper for meteringmaterial to said spreader, said outlet means being adjustably positionedrelative to the axis of rotation of the spreader whereby, duringoperation, material is spread out to be concentrated over a selectedangular sector, guide means supported on a bracket connected to saidframe, to present concave surfaces that surround at least a portion ofsaid rotary spreader, said guide means comprising a screen extendingover at least part of the selected angular sector to arrest the movementof controlled amounts of material ejected by said spreader, therebyallowing the material to fall by gravity to the ground in apredetermined spectrum and concentration, a first portion of said guidescreen being detachable from said bracket and securing means associatedwith said bracket to retain said first portion at a second position inback of a second portion of said guide screen.
 16. An implement asclaimed in claim 15, wherein said outlet means comprises an outlet portin the bottom of said hopper and control discs, each with outletopenings that can be placed in register with said port, said discs beinglocated between said hopper and said spreader.
 17. An implement asclaimed in claim 15, wherein said second portion is connectable to saidbracket by a readily detachable fastening member on said bracket.
 18. Animplement as claimed in claim 15, wherein said first portion of theguide screen is pivotally connected to said second portion which isfixed to said bracket.
 19. An implement as claimed in claim 18, whereinsaid first portion is turnable relative to said second portion about apivot whose axis extends substantially parallel to the axis of rotationof said spreader.
 20. An implement as claimed in claim 15, wherein saidfirst portion is connected to said second portion at a point which is ata maximum distance from the axis of rotation of said spreader, saidguide screen being positioned whereby the distance between said axis andthe screen progressively decreases in both directions when seen in topplan view.
 21. An implement as claimed in claim 15, wherein the firstportion of said guide screen has one of its ends located adjacent to, aradial line which, in plan view, passes through the axis of rotation ofsaid spreader and through said outlet means.
 22. An implement as claimedin claim 15, wherein said guide screen has a length of not more than 2meters.
 23. An implement as claimed in claim 15, wherein the length ofsaid guide screen is less than about 1 meter.
 24. A spreading implementcomprising a transportable frame, with a hopper and a rotary spreaderbeing mounted on said frame, said spreader being located below saidhopper and adjustable outlet means in said hopper for metering materialto said spreader, said outlet means being adjustably positioned relativeto the axis of rotation of the spreader whereby, during operation,material is spread out to be concentrated over a selected angularsector, gUide means supported on said implement to present concavesurfaces that surround at least a portion of said rotary spreader, saidguide means extending over at least part of the selected angular sectorto arrest the movement of controlled amounts of material ejected by saidspreader, thereby allowing the material to fall by gravity to the groundin a predetermined spectrum and concentration, said guide meanscomprising a guide screen, the area of which is adjustable to presentmore or less concave surfaces adjacent said spreader.
 25. A spreadingimplement comprising a transportable frame, with a hopper and a rotaryspreader being mounted on said frame, said spreader being located belowsaid hopper and adjustable outlet means in said hopper for meteringmaterial to said spreader, said outlet means being adjustably positionedrelative to the axis of rotation of the spreader whereby, duringoperation, material is spread out to be concentrated over a selectedangular sector, guide means supported on said implement to presentconcave surfaces that surround at least a portion of said rotaryspreader, said guide means extending over the selected angular sector toarrest the movement of controlled amounts of material ejected by saidspreader, thereby allowing the material to fall by gravity to the groundin a predetermined spectrum and concentration, the distance between saidconcave surfaces and the axis of rotation of said spreader being varied,said guide means comprising a screen positioned to surround a portion ofsaid spreader whereby the trajectory of particles of ejected materialintercepted by said screen are at angles of 45* - 135* relative totangents to said screen at the points of impact.
 26. An implement asclaimed in claim 25, wherein said guide screen subtends a maximum angleof about 240* at the axis of rotation of said spreader and one end ofsaid guide screen is located adjacent a radial line extending from saidaxis through the center of said outlet port.
 27. An implement as claimedin claim 25, wherein the lowermost edge of said guide screen is locatedat a distance above ground level which is not more than half thedistance of said spreader above the ground.
 28. An implement as claimedin claim 25, wherein, not less than about half the height of said guidescreen is located above said spreader.
 29. An implement as claimed inclaim 28, wherein said guide screen is fastened to said implementadjacent the upper rim of said hopper and the latter is located directlyover and above said spreader.
 30. A spreading implement comprising atransportable frame, with a hopper and a rotary spreader being mountedon said frame, said spreader being located below said hopper and outletmeans with at least one outlet opening being provided in the lower endof the hopper for metering material from said hopper to said spreader,said outlet means being positioned in a predetermined place relative tothe axis of rotation of the spreader whereby material is spread out overonly an angular sector, guide means supported on said implement topresent concave surfaces that surround at least a portion of said rotaryspreader, said guide means extending at least substantially over theselected angular sector to arrest the movement of ejected material, thedistance between said concave surfaces and the axis of rotation of saidspreader being varied, a radial line extending from the axis of rotationof said spreader through said outlet opening being inclined at an angleof about 70* to a further radial line passing through that point of saidguide means which is at the greatest distance from the axis of rotationof said spreader.
 31. A spreading implement comprising a transportableframe, with a hopper and a rotary spreader being mounted on said frame,said spreader being located below said hopper and outlet means with atleast one outlet opening being provided in the lower end of the hopperfor metering material to said spreader, durinG operation of the devicesaid outlet means being positioned in a predetermined place relative tothe axis of rotation of the spreader whereby material ejected from saidspreader is spread out over only an angular sector, guide meanssupported on said implement to present concave surfaces that surround atleast a portion of said rotary spreader, said guide means extending atleast substantially over the selected angular sector to arrest themovement of ejected material, the distance between said concave surfacesand the axis of rotation of said spreader being varied, that area ofsaid surface on said guide means which is most distal from the axis ofrotation of said spreader being angularly spaced from a radial lineextending from the axis of rotation of said spreader through said outletopening, at least part of said concave surfaces extending around thespreader from said most distal area of the guide means in the directionof rotation of said spreading member, whereby the distance between atleast a portion of said part of the concave surfaces and said axis ofrotation decreases as seen in the direction of rotation of saidspreader.
 32. An implement as claimed in claim 24, wherein said guidescreen is supported on bracket means attached to said frame and an upperbracket of said bracket means effects a connection between said screenand said hopper.
 33. An implement as claimed in claim 32, wherein saidupper bracket is connected to said hopper at three substantially equallyspaced-apart points.
 34. An implement as claimed in claim 32, wherein alower bracket of said bracket means is spaced from the ground by adistance of not more than about 10 centimeters.
 35. An implement asclaimed in claim 34, wherein at least one stiffening element extendsbetween said upper and lower brackets to increase the rigidity of saidscreen.
 36. An implement as claimed in claim 35, wherein said stiffeningelement is resilient to permit upward and lateral deflections of saidlower bracket relative to said upper bracket.